Scaling Behaviors of LLM Reinforcement Learning Post-Training: An Empirical Study in Mathematical Reasoning

Fuente: arXiv
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Auteurs principaux: Tan, Zelin, Geng, Hejia, Yu, Xiaohang, Zhang, Mulei, Wan, Guancheng, Zhou, Yifan, He, Qiang, Xue, Xiangyuan, Zhou, Heng, Fan, Yutao, Li, Zhongzhi, Zhang, Zaibin, Zhang, Guibin, Zhang, Chen, Yin, Zhenfei, Torr, Philip, Bai, Lei
Format: Preprint
Publié: 2025
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author Tan, Zelin
Geng, Hejia
Yu, Xiaohang
Zhang, Mulei
Wan, Guancheng
Zhou, Yifan
He, Qiang
Xue, Xiangyuan
Zhou, Heng
Fan, Yutao
Li, Zhongzhi
Zhang, Zaibin
Zhang, Guibin
Zhang, Chen
Yin, Zhenfei
Torr, Philip
Bai, Lei
author_facet Tan, Zelin
Geng, Hejia
Yu, Xiaohang
Zhang, Mulei
Wan, Guancheng
Zhou, Yifan
He, Qiang
Xue, Xiangyuan
Zhou, Heng
Fan, Yutao
Li, Zhongzhi
Zhang, Zaibin
Zhang, Guibin
Zhang, Chen
Yin, Zhenfei
Torr, Philip
Bai, Lei
contents While scaling laws for large language models (LLMs) during pre-training have been extensively studied, their behavior under reinforcement learning (RL) post-training remains largely unexplored. This paper presents a systematic empirical investigation of scaling behaviors in RL-based post-training, with a particular focus on mathematical reasoning. Based on a set of experiments across the full Qwen2.5 dense model series (0.5B to 72B), we characterize how model scale, data volume, and computational budget interact to shape performance. Our analysis leads to four key findings: 1. Larger models consistently exhibit superior learning efficiency on both compute and data metrics. 2. The relationship between test loss, compute, and data can be modeled by a predictive power-law which is robust across both base and instruction-tuned models. 3. Although larger models exhibit higher learning efficiency, the analytical learning efficiency term k(N) in the power-law reveals a latent saturation trend in learning efficiency as model size continues to increase. 4. In data-constrained regimes, repeated reuse of high-quality data proves highly effective, as final performance is primarily governed by the total number of optimization steps rather than the uniqueness of samples. Collectively, these results provide a principled foundation and practical guidelines for efficiently scaling the reasoning capabilities of LLMs through RL post-training.
format Preprint
id arxiv_https___arxiv_org_abs_2509_25300
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Scaling Behaviors of LLM Reinforcement Learning Post-Training: An Empirical Study in Mathematical Reasoning
Tan, Zelin
Geng, Hejia
Yu, Xiaohang
Zhang, Mulei
Wan, Guancheng
Zhou, Yifan
He, Qiang
Xue, Xiangyuan
Zhou, Heng
Fan, Yutao
Li, Zhongzhi
Zhang, Zaibin
Zhang, Guibin
Zhang, Chen
Yin, Zhenfei
Torr, Philip
Bai, Lei
Machine Learning
Artificial Intelligence
While scaling laws for large language models (LLMs) during pre-training have been extensively studied, their behavior under reinforcement learning (RL) post-training remains largely unexplored. This paper presents a systematic empirical investigation of scaling behaviors in RL-based post-training, with a particular focus on mathematical reasoning. Based on a set of experiments across the full Qwen2.5 dense model series (0.5B to 72B), we characterize how model scale, data volume, and computational budget interact to shape performance. Our analysis leads to four key findings: 1. Larger models consistently exhibit superior learning efficiency on both compute and data metrics. 2. The relationship between test loss, compute, and data can be modeled by a predictive power-law which is robust across both base and instruction-tuned models. 3. Although larger models exhibit higher learning efficiency, the analytical learning efficiency term k(N) in the power-law reveals a latent saturation trend in learning efficiency as model size continues to increase. 4. In data-constrained regimes, repeated reuse of high-quality data proves highly effective, as final performance is primarily governed by the total number of optimization steps rather than the uniqueness of samples. Collectively, these results provide a principled foundation and practical guidelines for efficiently scaling the reasoning capabilities of LLMs through RL post-training.
title Scaling Behaviors of LLM Reinforcement Learning Post-Training: An Empirical Study in Mathematical Reasoning
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2509.25300